Utilization of kelp and similar aquatic plants.



T. BOBERG & N. TESTRUP. UTILIZATION OF KELP AND SIMILAR AQUATIC PLANTS.

APPLICATION FILED DEC.l8| 19M.

Patented Mar. 28, 1916.-

VL an UNITED STATES PATENT onrrcn.

TEOFRON BOBERG AND NILS TESTRUP, OF LONDON, ENGLAND, ASSIGNORS TO TECHNO- CHEMICAL LABORATORIES LIMITED, OF LONDON, ENGLAND.

Specification of Letters Patent.

Patented Mar. 28, 1916.

Application filed December 18, 1914. Serial No. 877,978.

T 0 all whom it may concern Be it known that we, TEoFRoN Bonnnc, a subjectof the King of Sweden, and residing at Fair-lawn, Clarence Road, Clapham Park, London, S. W1, England, and NILS TESTRUP, a subject of the King of Great Britain and Ireland, and residing at 3 Dean Farrar street, London, S.W'., England, have invented certain-new and useful Improvements in and Relating to the Utilizationof Kelp and. Similar Aquatic Plants, of which the following is a specification.

This invention relates to the utilization of kelp and similar aquatic plants for the recovery of sodium and potassium salts or iodin or both therefrom and is particularly applicable to the treatment of giant kelps of the type Nereocg stis Luetltena, Macrocystz's pyrifera and Pelagophyous porra (see Journal Franklin Institute 1913, Vol. CLXXVI, 4), in which the alkali salts (exceeding in some cases 35%) are present in amount to represent a value greater even than that of the iodin.

We have ascertained that heating of the wet weed in a pulped state to an elevated temperature without permitting evaporation will secure destruction of the slimy matter which binds the moisture (and its dissolved salts) in the plant and will permit of expressing this liquid from the plant with relative ease after such a treatment.

As a result the method proposed by Eken-- berg of rendering the water expressible from peat (see Journal of the Iron and Steel Institute 1909) becomes avallable for this purpose. In carrying out the present invention therefore the kelp or the like is first reduced to awatery pulp, this pulp then forced under pressure through a heater and heat recuperator in such a manner as to destroy slimy water binding matters without permitting evaporation and without undue loss of'heat and the treated material then pressed to separate salt-containing solution 'whilethe solid is preferably further dried to render it available as fuel for the heat needs of the process. For this purpose methods and apparatus such as are proposed in British patent specifications Nos. 17010 of 1911, 17427 of 1912 and 24035) of 1012, for the treatment of peat may with advantage be employed.

As an instance of the character of the change which heat treatment can produce the following example may be given: A kelp which in the form of a pulp of some 90 per cent. water content contained 35 per cent. of alkali salts per 100 parts of dry solids, could be easily pressed to yield a firm press'cake, after having'been heated to a temperature of about 17 0 (1, or upward for a period of about twenty minutes. Some 25 parts of the alkali salts were now in the liquid While the remaining 10 parts were retained by the cake. Of the iodin some 90% was in the efliuent and of the nitrogen of the kelp of which this specimen contained some 1.2% calculated dry one-third was in the efliuent and two-thirds in the press cake. Some 10% of the organic mat-' ter of the original material had also become dissolved in the effluent. It will be seen, therefore, that in this particular instance the material behaved in much the same way and presents thesame circumstances as an average peat when considered from the standpoint of heat treatment as by wet carbonization.

In carrying out this invention in one form, the kelp, for example one of the giant kelps'above referred to, is gathered in any suitable way (see, for instance, Journal of the Franklin Institute, 1913, 4:, 347) and reduced to a condition which will render it suitable for pumping through tubular or other d-igesters and heat recuperators. The highly gelatinous condition of the material and its massive character present in this case certain special features it being, for example, desirable to reduce as far as possible the size of the particles of the pulp to such an extent that the time factor of change of condition is not unduly high (although particles several millimeters in diameter were completely altered by the time and temperature instanced) and it being further desirreduced by subjecting the pulped mass while preferably in a relatively thin layer to a partial vacuum or by conducting the pulping. under water or by both measures. Apparently, a content of insoluble matter of some 640% will, in most instances, yield a more or less fluid pulp with the macerate'd material. The pulp leaving the heater and after recuperation of its heat to the desired extent in the customary manner can be subjected to pressure filtration and a portion of the ellluent returned to be used in diluting a further quantity of raw pulp While the balance can be treated for recovery of its salts and the lilre in any convenient manner. The press cake may be washed to reduce the content of fusible salts in the massand the material gasified with byproduct recoveryor subjected to low temperature distillation to yield byrproducts, fuel gas, and

valuable residual char, suitable inter alia as filtering and. clarifying agent. The liquid expressed is preferably concentrated in an evaporator of the kind described in British Patents Nos'12462 of 1911 and 22670 of 1911, motive power for which is whollyor partly derived, for instance, from the bal- .an'ce of fuel available from the gasification or destructive distillation. The product may be either calcined to remove the organic matter and then in any suitable Way separated into its desired-constituents, or the concern trated syrup'or dried residue may be incorporated with the fuel in the gasifier or retort and after its organic matter has been i so utilized to yield up a corresponding amount of heat and, to yield up nitrogen vwhich has passed into the effiuent with it the salts can be recovered the ashes or char.

It will be understood that according to the particular constituents of the aquatic plants treated or their relative'or'absolute' amounts, or its organic nature and similar .factorsthe process can be carried out in-a large number of ditlerent Ways ofwhich the above are only examples.

Y P a g Shows one totreatment to separate dissolved'inorganic way in which the invention can be carried '50 into effect.

The wet weed is pulped in a pulper 1 and. falls thence into'a storage tank 2. A pump 3 draws it therefrom and forces it through aheat recuperator 4:, heater 5, vessel 6 in which the necessary time for completion of 'thc'change is given it,pipe 7, back through the regenerator 4 and by pipe 8 into a receiver 9 whence; it passes into'one' orother of the filter presses 10, the expressed liquid-I passing by pipe. 11 to the tank 12 and the residual solids on the opening of the press vinto the press-cake bunker 13. Before open-- ing the press the cake is-washed, the Washings as they diminish in strength being caught respectwely-in'tanks 14 and l5 to by lixiviation' of r 4 of the water while simultaneously subjecting t to pressure. suiiicient to restrain ebullition,

' ter' by filter pressing.

18 and pipe 19. The press-cakes from the bunker 13 are pressed further in.a powerful band press 20, elevated therefrom by an elevator 21 and carried by a conveyer 22 to a byproduct-recovery gas producer 23 the sul fate liquor from which is concentrated in evaporator Qiand the gas from which is used in part to heat steam raising boiler'25 and inpart to. operate the gas engine 26- driving the compressor 27 and film distributer pump- 28 of the evaporator 29 which concentrates the liquid from tank 12 and discharges concentrate into tank 30 and distilled water into tank 31, whence the latter can ,by pump 32 be raised to tank. 16 for use in press-cake washing.

Having now described our invention what We claim as new and desire to secure by Letters Patent is v 1. In the recovery of sodium, potassium. salts or iodin from aquatic plants the method consisting in heatingthe wet plant to a teinperature above the boiling point of the Wa ter and, under such pressure as tcrprevent tions and. separating the desired chemical product from the aqueous portion; as set forth.

2. The method of utilizing aquatic plants consisting in macerating the wet plant to a Watery pulp, continuously'forcing saidplup through a heating zone and raising it there in to a temperature above theboiling point i causing the heated mass, so soon as its water bindingproperties have been 'substantially destroyed by said heating, to-impart its heat to coolerpulp awaiting treatment,

pressingthe treated cooled pulp, collecting the expressed liquid and subjecting the same -while avoiding undue inclusion of air in the resulting pulp,.l1eating the pulp while containing some 90% of Water to a temperature of about 170 G. for some 20 mihutcsunder a pressure suificient to prevent evaporation,

cooling the treated material to a temperature of, about 30 Grandremoving aqueous mat- 4:. In. the recovery of valuable chemical" substances from aquatic plants. reducing the latter While wet-to the condition of a pulp by macerati-ng-them under Water, destroying the slimy water binding matters thereof by digestion at an elevated temperature and un der pressure, expressing the liberated aqueous matter, and admixing expressed aqueous matter with untreated material about to be digested.

5. In the recovery of valuable chemical substances from aquatic plants, destroying the water binding mattersthereofby digestion of the wet material, thereafter expressing the liberated egqueous matter, evaporating a portion of "the expressed aqueous matter for the obtaining of salts therefrom and admixing a further portion of the expressed copies qt this patent may be obtained tor five cents each, by addressing the "commissioner-"o! Patents,"

aqueous matter with a succeeding quan tity names to this specification in the presence of two subscribing witnesses.

TEOFRON BOBERG.

NILS TESTRUP.

Witnesses:

BEBTRAM H.- MATTHEWS, WILLIAM H. Bran.

Washington. D. 0." i 

